Shoe sole and method of making same



Nov. 27, 1956 R. W. POOLEY SHOE SOLE AND METHOD OF MAKING SAME Filed May 21, 1954 IN V EN TOR.

A TTORNE Y United States Patent SHOE SOLE AND METHOD OF MAKING SAME Robert W. Pooley, South Bend, Ind., assignor to United States Rubber Company, New York, N. Y., a corporation of New Jersey Application May 21, 1954, Serial No. 431,479

Claims. (Cl. 154-106) This invention relates to a multi-colored, flexible, resilient laminate made of a closed-cell, expanded, vulcanized, fused mixture of a thermoplastic vinyl resin, a high-boiling organic liquid plasticizer therefor and a butadiene-acrylonitrile rubbery copolymer. The laminate of my invention is particularly characterized by the sharpness of the lines of demarcation of differently colored layers and by the fact that these differently colored layers are integrally bonded together during manufacture without the use of any cement or solvent which would add to the expense and cause trouble with delamination. In accordance with my invention integral bonding of adjacent layers is achieved as a result of fusion of the mixture and vulcanization of the rubbery copolymer during processing which cause sutficient coalescence of the material of the adjacent layers with each other at the interfaces to effect a strong integral bond but insufiiciently to cause merger to such an extent as to form interfacial zones of appreciable thickness. Actually in spite of the integral bond, the lines of separation of the adjacent layers in the finished laminate are so narrow that they present no width to the unaided human eye. Furthermore, in spite 'of merger at the interface to a degree sufficient to give a truly integral bond, the lines of demarcation are perfectly sharp and straight which adds greatly to the sales appeal.

My invention is particularly applicable to the manufacture of the laminate described above in sheet form' with the layers of the differently colored stocks extending parallel to the faces of the sheet. Such a sheet can readily be made with a roughened face on one side whereby by cutting the sheet transversely to the differently colored laminations there can be obtained shoe soles having a most attractive edge characterized by the sharpness and straightness of the stripes exposed in the cutting operation.

The principal object of my invention is to provide a new laminate which does not require the use of cement, solvent or other special technique to secure bonding of the several laminae together. Another object is to provide a laminate of a closed-cell, flexible, resilient, expanded composition of matter which is especially characterized'by the straightness and sharpness of the lines of demarcation visible at the exposed'edges of the laminate when it is cut transversely of the laminae into any desired articles, especially shoe soles which can be made into attractive sandals by application of straps or other fastening means. Another object is to provide a highly attractive and useful shoe soling material and shoe soles made therefrom by a simple dieing-out operation. Another object is to provide a novel method for the manufacture of the aforementioned new articles of manufacture. Numerous other objects will more fully hereinafter appear.

In the accompanying drawings, which portray one method of making the multi-colored laminate of my invention,

Fig. l portrays the layers of differently colored sheeted stock before the pre-molding step;

Fig. 2 portrays the pre-molding step;

Fig. 3 is a perspective of the miniature laminated premolded sheet produced in Fig. 2;

Fig. 4 is an edge view of the final expanded and cured sheet;

Fig. 5 is a plan view of the sheet indicating cuts defining soles made therefrom; I

Fig. 6 is a perspective of a finished sole; and

Fig. 7 is an enlarged plan view of a portion 'of a typical tread design.

My invention is based upon the discovery that a very useful and highly attractive article of manufacture can be made by forming a plurality of differently colored mixtures of a solid, shapable, non-sticky dispersion of a thermoplastic vinyl resin and a high-boiling organic liquid plasticizer therefor in a butadiene-acrylonitrile rubbery copolymer as the continuous. phase, which mixtures include pigmenting material, a chemical blowing agent, and vulcanizing agents for the rubbery copolymer, sheeting out these mixtures, plying up layers of the differently colored sheets with differently colored layers adjacent to one another, and thereafter heating the pliedup assembly and effecting decomposition of the blowing agent and expansion of the mixture to closed-cell cellular form, fusion of the resin, plasticizer and rubbery copoly mer into a uniform homogeneous blend, vulcanization of the rubbery copolymer and integral bonding of contiguous layers to each other at the interfaces, whereby there is formed a laminated article comprising a plurality of parallel differently colored closed-cell expanded layers integrally bonded together at their interfaces with sharp straight lines of demarcation therebetween. In the pre-' ferred embodiment of my invention the thickness and number of the sheets originally plied up are such that the final sheet has a thickness suitable for shoe soling.

A typical method. of making the multi-colorecl laminate of my invention comprises pre-molding under heat and confining positive mechanical. pressure a plied up assembly of. differently colored layers of a thermo-- plastic vinyl resin, a high-boiling organic liquid plasticizer therefor and a butadiene-acrylonitrile rubbery copolymer, the latter being in the continuous phase, each to prevent final expansion of the mixture, cooling the mix ture while maintaining the confining positive mechanical pressure thereupon, removing the mixture from the premolding press, and heating the resulting miniature shape under conditions of free expansion toexpand it to final form by means of the gas which was evolved during the pre-molding step and to complete the cure of the rubbery copolymer.

My invention is based upon the discovery that when differently colored layers of stock are treated in the foregoing manner they bond together integrally during the processing by which the expansion and curing are performed and form sharp straight lines of demarcation between difierently colored adjacent layers whereby there is obtained a laminated expanded article in which the differently colored layers are integrally bonded to'one another without migration of the differently colored stock into one another in such a way as to destroy the sharpness of delineation and whereby distortion of the layers during processing is prevented. The result is that in the final article the differently colored layers are sharply difierem planar or flat so that upon cutting the laminate at an V angle tothe laminae thereof along any line therein a most attractive.stripedsurfaceis revealed.

*Upon cutting the resulting laminated article at an angle. to the planes of the different colored layers which compose it, there is obtained an unusually attractive striped sll ltfacewhich is characteri'zedby the, sharpness with which the stripes of differently coloredlayers presentthemselvesv "to the eye. The. cutting of. the; finalexpanded CUITBCLEHZlil' cIe can be done'at right angles 'to'tlie laminae or atiany. other desired angle. Usually the.cuttingis.done; at right angl'es.- p

By. making a flat sheet. o'flstock'in the mannelidescribed above Withthe laminae running, parallel to thelplanar. sur- 7 4e 7 vertically by the lateral pressure of the stock during the miniaturemoldingstepwherebyto seal off the moldcom pletely' and prevent flash and escape of stock and of the gas generated in this step, .as described and claimed in my copending application Serial No. 313,752, filed October 8, 1952, now U. S. 2,713,699. Use of-sucha gasket prevents any distortion of the layers of'the stock.

7 objectisremoved; his then heatediundericonditionsTot free expansion, typically at temperatures of the" order of i faces-bf the sheet and by dieing-out pieces thereoihaying the. Shapeof a shoe sole,there is obtained van;exceedingly attractive shoe sole. to which straps, or. anyaother suitable foot-attaching; structure can be secured. toform a sandal:

orother article offfoot wean] S'uchshoe solesvhaveggreat eye appeal and have. found a ready market because. of

the unusually sharp manner in whichlhe difierently: 6011' ored stripes of expanded; stock are manifested at the edge; The e Shoe soles'are comfortable tostheawearer because of their compressibility andflexibility-which cause. I I them torconform comfortably IOIthB contour oi thelfoot, and'to reduce the shock of impactjwiththegrounds.. They have. a' true cushioning,nature.v In thepreferred embodiment, they have a smooth upper surface for greater foot [comfort and a roughened tread base, the latter'being imparted in any suitable way. asby having. one. face, of the mold, in which the aforementioned,prermolding is. performed, engraved with any desired; non-skid tread. patternin miniature. Sucha.tread'patternprevents un-' .due slipping on wet surfaces, is Z In practicing my invention, Ilmuch prefer to form the initial *mixtures-in accordancewiththe teachings .of U. S.

" patentto'Daly et al.,-2',570,l82 issued October 9, 1951,

in accordance with which;I disperse an ,unfused mixture 'After fusion, decomposition of blowing agent and par tial: curing; haveibeen; achieved;: the miniature article; is cooled as by admitting cooling water to. the platensof, the press whereupontthe-mold is openeda'a'ndtheminiature- 300 ,3509'F.,.to.-efiecttfinall expansiqn and-cure; The de- 7 gree of expansion brought about is usuallyequal to at least twice in each" direction, corresponding to at least "an eightfold volumetric expansion. :The degree of ex-' pansion canbe controlledyby varying thejamount and types; of blowingagent. and should be taken; into'raccojunt in. calculating the size and proportions; off timepieces: off

stock. originallyused and of the. pre-moldingicayity Thevinyl resinwillsalmostzinvariablybepqlyyinyljchl'o i ride. or a resinous copolymer 05 a major-, propoition ofvinyl chloride'and alminorproportiomofi copo'lyrnerizable-i of a thermoplastic vinyl'resin and a high-boilingorganicrliquid plasticizer therefor whichr is substantially: a nonsolvent for the resin atordinaryIternperaturebuttis capable of dissolving the jsarne'nponheating toan elevated temperature, in a hutadiene-acrylonitril'rubbery 'copoly,--

mer 'a s the continuous; phase. Several different batches,

. dependingi upon'the number of colorsgdesiredin thefinal.

article, are-prepared, each'be'ing diflferently'pigmented'. 1 Each Of'the batches contains achemicalblowing agent andvulc'aniaingagents for the copolyme r.

"These 5 mix plex,G60.- --;L

I can'use any rubbery copolymer of but-adienei andlf acrylo nitrilep These.rubberyg'copolymers arezzcqmmonly known asflBuna-NJI 'The-combined.acnylonitrileicontent? tures are dry and'moldable and free. fromihe stickiness:

w hichlhas been a major difficulty'with plastisols; a These mixturesqare. then sheeted out as. on al.sheeti iig:rni]l-or rubber'calendei to formrlayers ofuniform thickness. The

. thickness of these layers Will dependuponthe thickness of the layers desired in the finallflticle; The resulting sheets; f '7 orportions'thereof having an'area f commensurate'yvith: V V 7 that of the pre-molding cavity 'are. then charged into such cavity,using difierentlylcolored layers to achieVethe eEeCt;

desired in thelfin'al amass. The pre -molding; cavity: is:

the gasev'olved the blowing ageht during.preamolding. 1

Shouldsa small amount ofgasescape, forwexampleat a.

' cornerfofhthefframe mold, it may: result ina slight dis? tortion of thelayers of. stock adjacent the point of escape, necessitating discarding such distorted portion- .during; the 1 subsequent cutting op eration'.

If desired, l may provide a thick elastic gasket around: 7 theihteritir of-;thewallsof themold, which gasketisi spacedsfrom .the upper .platen oflthe press-to allow escape 1' V of Iain and gas. above. the initial1,charge blllnlSf expanded Paracril. I have,alsq successfullyausedthercopolyme bery copolymer cansvary; widelygf. 'Typicallyiltemployrfroi vsome applications the propontmns-justgiven:willb en monomer containingv an ethylenic group e g.,;vinyl. ace.

tate, vinylidenei' chloride, diethyl. maleate,1--d iethyl fu-; marate; etc.. I prefer. to; use. copolymers; madeifrom;

' 85-95% vinyl chloride and? 1-5-5 %..copolymerizable'monw V o'mer. The, vinyl resin. should 1 be cornplete'lywompatiblel with the rubberycopolymen and should. becapablezof being dissolved. by-the plasticizer, uponrheatingto an=-ele vatedtemperature, i. e.,.300? Fror higher lto form a geli. Any high-boiling organic: liquid plasticizer capable: ofdissolving the vinylresinupon heatinggcanzbeusedf The? plasticizershouldbe compatible with:the5ruhher copoly mer. It usually is fa'n 'esterjether or; ketonc': Examplesr of suitable plasticizers are dioctylnphthalatej. di'butyl. seba cate, dioctyl sebacate,;-linear. polyester res-injplasticiie'rs such, as those disclosed. at. ln'dEngfChem 37,55045 (1945 for example, Paraplex. r- 60,1? sand-plasticizers, 7

made by introducing epoxy; gnOHps-into 'a-drlying'jioil, e: g, soybean. oil, an exa'mplegof; the: latten type-being generally ranges-from 151m. 40 a. Examples f suitable rubbery copolymers' are' -those sold under: the atradeznam sold' as Hycar (QR-l; and-ziChemignm-z.

V The relative prop ortions; of resin; plasticizen land tube to 66 of the resin fromjl 0 :to %;of;tlierplasticize wandfrom 16 150 of the copolymer, thesevperceniagesq f-being by iweightebasedionithe sum:of:theseethreeingredients' 'alone and'totaling ."Thesepercenrages arepreferredr because: they giye a producti havingrthe flexibility; are compressibility desire templateds Fin} the; slioefsole. f

For; certain .uses ,1.whereunusually; goedzsitoc the attainment-lot. unusual shit lasorbingjprcperticsrby the use orrm 42m 66%nof=theresin-froznrl4 toiZOP/fr of theplasticizeriand from fZQ to 38% e vention: will 4 have prop ertionsigv'other than these" h As. the. chemical. blowingg'agent,.Lprefer:tosuse thosc V which liberate nitrogen; gash Examples'are.Ilinitrosopet t methylenetetramine (sold as Unicel ND") alpha alp' hydrazide) (sold as Celogen). The amount of the blowing agent used may vary widely depending upon the particular blowing agent employed and the proportion thereof used.

Any of the conventional vulcanizring agents, compounding agents, fillers, pigments, etc. commonly used in the rubber industry may be incorporated in the mixture. I generally prefer to employ sulfur as a vulcanizing agent in conjunction with known vulcanizing accelerators and activators. I may also include conventional antioxidants for the rubbery copolymer and known stabilizers for the resin.

My products are almost 100% of the closed-cell type. As a result, they show very little moisture absorption. This is highly advantageous in .a shoe sole. Typically my products have a water absorption figure substantially less than of their weight when they are submerged in water for 72 hours.

The density of my products is usually not over pounds per cubic foot and often ranges from 9 to 12 pounds per cubic foot. The compressive resistance of my products is at least 0.8 pound per square inch at 25% compression and may range up to pounds per square inch, often ranging from 6 to 16 pounds per square inch. In the typical practice of my invention, all layers of the laminate have a compressive resistance of 6 to 16 p. s. i. and a density of 9 to 12 pounds per cubic foot. The compressive resistance, or yieldability, of the product can be controlled by varying the relative proportions of the three principal components and 'by adjusting the amount and type of vulcanizing agents for the copolymer.

A marked advantage of my material for shoe soling is the fact that relatively very high compressive resistance can be achieved at relatively low density. For example, by my invention I can make shoe soling having a 25 compressive resistance of 12 .to 16 pounds per square inch and a densityof 10 to 12 pounds per cubic foot.

After pre-molding is complete, the miniature premolded article should be cooled down to below 150 F. before opening the pro-molding press, in order to cause the miniature to have sufficient strength to retain the liberated gas. It will be understood that the gas evolved in the pre-molding step is under very high pressure, being either dissolved in the stock or maintaind therein in the form of very small bubbles or both, so that the stock must develop considerable strength in order to hold the gas.

It will be understood that my invention can be practiced with innumerable variations in the colors and arrangement of the differently colored layers. It will also be understood that my invention could in its broader aspects be practiced by placing in the pre-forming mold pieces of difierently colored stock arranged in a difierent manner than that described above. For example, sections of differently colored stock having the thickness of the frame mold could be disposed therein whereby there would be obtained a laminate having the difierently colored stripes appearing on the upper and lower surfaces thereof rather than at the edges thereof. Many other variations of my broad inventive concept will be apparent .to those skilled inthe art.

Although I have described my invention with particular emphasis on the method comprising a miniature premolding step followed by free expansion, I am not restricted to this method in the broader aspects of my invention but can use the method described and claimed in my copending application Serial No. 431,460, filed of even date herewith, in accordance with which the pre-molding under high pressure is eliminated. In applying the method of said application to the production of the multicolored laminate of my invention, differently colored mixtures made as described herein but containing an ultra accelerator in amount equal to from 1 to 5 parts per 100 parts of butadiene-acrylonitrile rubbery copolymer are formed. These mixtures are sheeted out in the usual way 65 sun 6 (at room or only moderately elevated temperature), as by calendering or by extrusion, whereupon a plurality of layers of difierently colored stock are placed in a mold (preferably a frame mold) in such a way as to substantially fill the mold therewith, whereupon the plied-up assembly is subjected to pressure and moderate heat to mechanically knit the adjacent layers together. The conditionsof time, temperature'and pressure in the sheeting step are so adjusted that the desired consolidation of the mixture into sheet form takes place without decomposition of the blowing agent,.fusion of the'three main ingredients, or curing of the rubbery copolymer and the conditions in the pre-molding step are so adjusted that the desired knitting of adjacent layers together is achieved without decomposition of the blowing agent, .without substantial fusion and with or without partial curing of the rubbery copolymer. The miniature plied-up assembly so obtained is removed without cooling the mold and heated at a temperature of at least 300' F. under conditions of free expansion todecompose the blowing agent, effect fusion of the resin, rubbery copolymer and plasticizer and complete the cure of the rubbery copolymer. The ultra accelerator partially cures the rubbery copolymer either in the pre-molding step or during the initial portion of the final expansion step.

When shoe so-ling is produced by the method just described, a tread design can be imparted to one side of the laminate by using a plate engraved in negative with the tread design in miniature on one face of the plied-up assembly during the pre-molding step.

Many advantages of my invention will be obvious to those skilled in the art. A Very great advantage is that no cementing of the laminae is involved. Cementing would be highly objectionable because of the time re-.

or foxing to the sole and it eliminates the objections to such applied'edging or foxing. With my material, the same attractive edge is presented to the eye regardless of where the stock is cut. In other words, the striping is an integral part of my sole and my soles are ready for use immediately after theya're died-out.- 'Another advantage of my invention is that any suitable non-skid tread design can be obtained by the use of a molding plate having such design in the forming operation. V

The following are typical formulations which can" be used in the practice of my invention. All parts 'are by weight.

Example White Vinylite VYNW (Copolymer 0t vinyl chloride and 5% vinyl acetate) Diootyl Phthalate (plasticizer) 30 Dibutyl Sebaeate (plasticizer) Stabilizer for Vinyl Resin ur Benzothiazyl Disulfide Color Pigment (e. g., red, blue, green, etc.) 6 Titanium Dioxide Blowing Agent (p,p'-oxybis sulf-onyl hylrazide Buna N (Hycar OR15) Agerite Stalite (Anti-oxidant, a. mixture of monoand diheptylated amines) 1 1 1 Total All of the above ingredients except the two plasticizers,

the Hycar?andthe Agerite Stalite were dry blendedin a Hobart mixer to a uniform -mixture. The plasticizer was then I'addedto fliimixture and intimately. incorporate'd therewith. The H-ycar was-"banded ona* cold; rubber milll whereupon. the. AgeriteStalite wasin- V corporated tlierewith on the cold rnillafter which theuniform blend wh'ich had been preparediin-the Hobart-mixer was incorporated with the Hycar-Agerite Stalite? mix'-- ture on the-coldmil'l. v Milling was continued until a homo:

geneous dispersionwasobtainedl Care was taken'to keep the temperature of the mixture, below 1 80" F. to avoid fusioniofthe'mixture decomposition of the blowing agent; The mixture at this point contained: the rub bery;

c opolyjiier in the continuous phase withgth eresin, plasj ticiz er' and other ing'redients in: the discontinuousphaser ,Diiferently colore'd mix'es having: the above formula-i tion were slieeted out and converted into a-multi-color'ed laminate infthe manner described herein.

Tl'ie formulation-of Example I typically" results in a lproduct' with a compressive resistance of 6-8 p. s. i.

' density of about 10 12 pounds perlcubic foot.

Where the-two-stage expansion process is used,iI may presscurethe formulationofExample I for ZO minutes at"0F. and may press cure the formulationsof E xamplesfll andHT for l 5-minutes atf315v F: lfa laminate of Example I and Examples If or TIT-is being prepared,

intermediate conditions 0? time and temperature maybe: a used I may perform the'final expansion of all three:

examples by heating. the .pre-m'old ed laminates 20'30 minutesat 320 3 4UF: The-formulationsmay bemod i- 'fiedlin lorderl thatpressicu ringior. final, expansion vor both may takeplace atconsiderably different times and temperatures from those stated.

'I'he formulations of-Examples I to lILmay alternatively; be processedby theoneestage or low temperature press ing; technique of; my aforementioned: application Serial N0.2131;460-withsubstantially equivalent results; 1

Multi-colored laminates made'from-th'e formulations of '1 Exarnplesr'L {to- III, processed-ineither of thefiways describedaliove can be died-out intoshoe';soles=havingigreat sals'appealandfoot-comfort;3; i a

' Referring now? top-the: drawings,

, V imitatesand 3 of stoclslsprepared as described above 'in-difierent colors, 1 f

marcation therebetween at exposed surfaces of said lami:

forexamplegred; white: and blueprespectively, are placed in; a frame mold which isrformedbythe platen s 'andl v 5 of arp'ress, rectangular frame 6 and tread design moldingr'n'emberfl (upon which the treaddesign is engraved l infminiature). The" thickness and size of sheets'l, 2 and :3 fissuchlthat themold cavity is substantially completely filled therewith when "the press is closed. The V pressxis clo'sed 'andheat is applied to the platens to efiiect fthe pre-molding operationi described above. The platens are then cooled to; bring thestock down 'to' a tempera' 'ture approaching; room temper'ature whereupon the pre- I V molded miniature sheet S is removed. Miniature sheet-8f 'is then expanded underlconditionsttotzfree'expansion in the rnanner de'scribed above 'tog give lt inal sheetiihaving the desired;tread? design. l shoesoles lfi are then cut H from sheet 9 asfindicated' in' Fi'gq jr Tread surface 1' j offsheet 9 1 and :sol es'ltl can have any desired non-skid pattern, for example, a pattern "embodying" pyramidal f projections; 12, 'as'shown in detailginfig, 7-. "The final; V 'sheet9 and-soleslfl arefcharacterized' by the sharpness; 1] and ist raightness of the lines of'demarcationbetween the adjacent differently colored sections and these same'sharp' straight lines of demarcation are apparent'regardless of theportionof sheet9which is cut; V g a l Having thusdescribed my invention, what I claimand desire to protect by Letters Patent is: l i f a V 1'. A' new article ofmanufacture comprising at flexible, resilient laminate ofi a"closed cell expanded, vulcanized,

fused: mixture 'of a thermoplastic vinyl resin; a h ighboilingorganic liquid plas'ticizer tliereforanda butadienei acrylonitrile rubbery copolynier, said laminate compris ing a plurality of parallel juxtaposed differently colored layers of said mixture g integrally bonded together at' their interfaces, said layers forming sharp straight linesof de nate transverse tosaid layers, allfofsaid layers having-a" compressive resistance of at least- 6 pounds' per square inch and a density of not over 15 pounds per cubic-foot; V

2. An article of manufacture as set' forth in claim 1' wherein the relative proportions of said resin',vsai d-plasti-j cizer. andsaidcopolymer are'equal to from lOto 66% I of said resin, from 10 t0 60% of; said plasticizer and; from-l6 to of-said copo'lymer, said percentages being by weight basedonthe sum ofthe weights of saidrthree 'ingredientsand totalling'100% t 1 3. As a new articlelof manufacture, a-sho'e sole*com-,

prising. a flat flexible sheet of a closed-cell, expanded, vulcanized, fused mixture-- of a thermoplastic vinyl resin,-

a high-boiling organic liquid plasticizer therefor and a5 butadiene-acrylonitrile rubbery copolymer, said sheet comprising 'a' plurality of parallellsuperimposeddiffer-- ently colored layers of said'mixtu-re" integrally bonded a together at their interfaces,- said-layers forming sharp straight lines of demarcation therebetween at the edges of said sheet, all of said layers havjingla-25% compres-ll sive resistance of from 6 to; 16 pounds per square'inch and a density of fr'onr9-to'l2 poundswper cubic'footi weight based-on thersum' of the weightsof said three ingredients and tota1ling'100%. l l

j 5. A shoe sole as' recitedin-claim 3having a tread facej having a non-skid tread design molded therein and a smooth upper face." g

a 6. The method which 'comprisesformin'g a plurality ofi 7 differently colored mixtures of a solid, shapa-ble,-- nonsticky ,dispersionof a thermoplastic vinyl resin an'da high boiling organic liquid plasticizers therefor in a butadiene- *ac-rylonitrile rubberyfcopolymer' as the continuous phase,

' said mixtures includingjlpigme nting materiah ach ei nieal blowing agent; and vuljc'a'nizingtagents for'sa-idcopolymer;

sheeting out said mixtures, plying 'up layers ofrthe differ ently colored sheetslv/ith difierentlyf colored layers adjal cent to one anotheryand' heating the pliedupf-assembly and effecting decomposition of the blowing agent and" 7 expansion 'ofthe'mixtures to'clcsed-cell cellularjform;

fusion of-the resin, plasticizerand rubbery copolymer into a-uni forrn homogeneousblend; and vulcanizationof the" V rubbery copoly-rner, and thereby;formingalaminatecom-' prising, a plurality ,of paraliel juxtaposed differently col j ored closed-cell-layers integrally; bonded z-t'ogether at'theiu 7 interfaces and formingfsharpjstraightlinesof? demarcat 'tion therebet-ween'. v x p l l .7. rhethod as setforth-jin claim 6 includinglthei" lfurther istep of cuttingi'the laminated 'article' preparedzas: Y a

defined in claim 6 transversely to the laminaefthereof f 7 wherebyan attractive surface havingi'difierently colored", '1;

I stripes with jsharplydefined'lines iof demarcation- :therebe' tweenis obtained; V V j j V .Themethod which cornprises forming a plurality. of

v 'difierently colored mixtures of a' solid, shapable,lnon; l

' sticky dispersion of a-thermoplastic'yiriylgresinand. high V said mixtures including pigmenting material, a chemical a blowing; agent, and vulcanizing agent sfo'r'saidcopolymer, l

sheeting out said-mixtures, plying up layers of the differl ently' colored sheets with differently colored layers-adj? cent to oneanother, heatingthe plied-up assembly-to afn- V elevatedternperature su'fieient to deee'mpose said bloiviiig agent, fuse said resin, plasticizer and copolymer into a single phase, partially vulcanize said copolymer sufiiciently to prevent escape of the gas evolved by said blowing agent and effect integral bonding of said layers at their interfaces without destroying the sharpness of the lines of demarcation therebetween, rigidly confining the assembly under positive mechanical pressure during said heating step, cooling the assembly while maintaining said pressure, removing the assembly from confinement, and heating it under conditions of free expansion to expand it to final form and complete the cure of said copolyme-r.

9. The method of making flexible, resilient, compressible shoe soles having sharply defined contrasting colored stripes extending completely around them which comprises forming a plurality of differently colored mixtures of a solid, shapable, non-sticky dispersion of 'a thermo plastic vinyl resin and a high-boiling organic liquid plasticizer therefor in a butadient-acrylonitrile rubbery copolymer as the continuous phase, said mixtures including pigmenting material, a chemical blowing agent, and vulcanizing agents for said copolymer, sheeting out said mixtures, plying up layers of the differently colored sheets with differently colored layers adjacent to one another, forming a non-skid tread design in miniature in an outer face of an outer ply, heating the plied-up assembly and effecting decomposition of the blowing agent and expansion of the mixture to closed-cell cellular 'form, fusion of the resin, plasticizer and rubbery copolymer into a uniform homogeneous blend, and vulcanization of the rubbery copolymer, and thereby forming a laminated sheet comprising a plurality of parallel juxtaposed differently colored closed-cell layers integrally bonded together at their interfaces with sharp straight lines of demarcation therebetween, and forming shoe soles from the resulting sheet by cutting it transversely to the laminations thereof.

10. The method of making flexible, resilient, compressible shoe soles having sharply defined contrasting colored stripes extending completely around them which comprises forming a plurality of difierently colored mixtures of a solid, shapable, non-sticky dispersion of a thermoplastic vinyl resin and a high-boiling organic liquid plasticizer therefor in a butadiene-acrylonitrile rubber copolymer as the continuous phase, said mixtures including pigmenting material, a chemical blowing agent, and Vulcanizing agents for said copolymer, sheeting out said mixtures, plying up layers of the diiferen-tly colored sheets with difierently colored layers adjacent to one another, heating the plied-up assembly to an elevated temperature sufficient to decompose said blowing agent, fuse said resin, plasticizer and copolymer into a single phase, partially vulcanize said copolymer sufliciently to prevent escape of the gas evolved by said blowing agent and eifect integral bonding of said layers at their interfaces without destroying the sharpness of the lines of demarcation therebetween, rigidly confining the assembly under positive mechanical pressure during said heating step, molding a nonskid tread pattern in miniature into the :outer face of an outer layer of :the assembly during said heating step, cooling the assembly While maintaining said pressure, remov ing the assembly from confinement, heating it under conditions of free expansion to expand it to final sheet form and complete the cure of said copolymer, and forming shoe soles from the resulting sheet by cutting it transversely to the laminations thereof.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A NEW ARTICLE OF MANUFACTURE COMPRISING A FLEXIBLE, RESILIENT LAMINATE OF A CLOSED-CELL, EXPANDED, VULCANIZED, FUSED MIXTURE OF A THERMOPLASTIC VINYL RESIN, A HIGHBOILING ORGANIC LIQUID PLASTICIZER THEREFOR AND A BUTADIENEACRYLONITRILE RUBBERY COPOLYMER, SAID LAMINATE COMPRISING A PLURALITY OF PARALLEL JUXTAPOSED DIFFERENTLY COLORED LAYRES OF SAID MIXTURE INTEGRALLY BONDED TOGETHER AT THEIR INTERFACES, SAID LAYERS FORMING SHARP STRAIGHT LINES OF DEMARCATION THEREBETWEEN AT EXPOSED SURFACES OF SAID LAMINATE TRANSVERSE TO SAID LAYERS, ALL OF SAID LAYERS HAVING A COMPRESSIVE RESISTANCE OF AT LEAST 6 POUNDS PER SQUARE INCH AND A DENSITY OF NOT OVER 15 POUNDS PER CUBIC FOOT. 